ICD-10-CM 2027
ICD-10 code for reflux
From the official ICD-10-CM alphabetic index entry “Reflux”. Page updated September 29, 2026.
About coding reflux
The ICD-10-CM code for reflux is K21.9 (Gastro-esophageal reflux disease without esophagitis). The official index lists 21 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on K21.9.
Within K21, choose K21.9 (without esophagitis) only when documentation doesn't support a more specific option: with esophagitis (K21.0).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific reflux codes (official index)
- acid K21.9 — Gastro-esophageal reflux disease without esophagitis
- esophageal K21.9 — Gastro-esophageal reflux disease without esophagitis
- with esophagitis (without bleeding) K21.00 — Gastro-esophageal reflux disease with esophagitis, without bleeding
- with bleeding K21.01 — Gastro-esophageal reflux disease with esophagitis, with bleeding
- newborn P78.83 — Newborn esophageal reflux
- gastroesophageal K21.9 — Gastro-esophageal reflux disease without esophagitis
- with esophagitis (without bleeding) K21.00 — Gastro-esophageal reflux disease with esophagitis, without bleeding
- with bleeding K21.01 — Gastro-esophageal reflux disease with esophagitis, with bleeding
- mitral
- ureteral
- vesicoureteral (with scarring) N13.70 — Vesicoureteral-reflux, unspecified
- with
- nephropathy N13.729 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, unspecified
- with hydroureter N13.739 — Vesicoureteral-reflux with reflux nephropathy with hydroureter, unspecified
- bilateral N13.732 — Vesicoureteral-reflux with reflux nephropathy with hydroureter, bilateral
- unilateral N13.731 — Vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral
- bilateral N13.722 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, bilateral
- unilateral N13.721 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, unilateral
- without hydroureter N13.729 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, unspecified
- bilateral N13.722 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, bilateral
- unilateral N13.721 — Vesicoureteral-reflux with reflux nephropathy without hydroureter, unilateral
- pyelonephritis (chronic) N11.0 — Nonobstructive reflux-associated chronic pyelonephritis
- congenital Q62.7 — Congenital vesico-uretero-renal reflux
- without nephropathy N13.71 — Vesicoureteral-reflux without reflux nephropathy
Common questions about reflux ICD-10 codes
What is the ICD-10 code for reflux?
- K21.9 — Gastro-esophageal reflux disease without esophagitis. More specific codes apply when the documentation supports them: K21.9, K21.9, K21.00, K21.01 and others below.
What is the ICD-10 code for acid reflux?
- K21.9 — Gastro-esophageal reflux disease without esophagitis.
What is the ICD-10 code for esophageal reflux?
- K21.9 — Gastro-esophageal reflux disease without esophagitis.
What is the ICD-10 code for gastroesophageal reflux?
- K21.9 — Gastro-esophageal reflux disease without esophagitis.
What is the ICD-10 code for vesicoureteral reflux?
- N13.70 — Vesicoureteral-reflux, unspecified.
Is K21.9 billable?
- Yes. K21.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K21.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K21.9 as a principal diagnosis.
Is K21.9 a CC or MCC?
- No. K21.9 is neither a CC nor an MCC under MS-DRG v44.0.